Process for treating oil shale



J. B. JENSON PROCESS FOR TREATING OIL SHALE April 15 1924.

Fiied Sept. 18

3114x141 ult 1, James. wom

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patented pr. i5, 92.

T AT

JAMES B. JENSON, OF SALT LAKE CITY, UTAH.

PROCESS BOB TREATING OIL SHAIIE.

Application led September 18, 1919. Serial No. 324,280.

To all whom it may concern.

Be it known that I, JAMES B. JENsoN, a citizen of the United States,residing at Salt Lake City, in the county of Salt Lake and State ofUtah, have invented certain new and useful Improvements in Processes forTreating Oil Shale, of which the following is a specification. v

In extracting the oil froml oil bearing shales under the ,presentmethods, three serious difficulties are encountered. The first is thefluxing of the rshale within the retort, when high grade massive shaleis being treated; the` second is the formation of a very largeproportion of unsaturated hydrocarbons which form a complex mass andmakes refining difficult, as well as also causing high refining loss,and the third is the decomposing of the lighter gases lEroduced at lowtemperature by bringing t em into contact with portions of the retort orother gases vof a higher temperature than that at which they wereproduced. The iiuxing of the shaleunder treatment, is caused by gasesfrom the hotter ortions of the retort coming in contact with the coldershales which' are being charged into the retort, and said gasescondensing; thereby making an oily, viscid mass, which, when it reachesthe heat zones and the partially volatilized'oils, and is againvaporized leaves a solid mass consisting of the broken pieces of shalecemented together by tixed carbon or coke, often found so hard that itis necessary to use steel bars to dislodge it. This necessarily causesadditional expense and the delay of shutting down the plant.

I have found thatvif a proper temperature is maintained within theretort and condensation prevented .that fluxing is avoided. I havediscovered and perfected a stage eduction process whereby the bituminousshale is treated in separate chambers, at predetermined temperaturesforv each chamber, for a suiiicient length of time to educt suchhydrocarbons (volatilize the oil content) as may be volatilized at thatparticular temperature and while this step in my procem is being carriedout, I withdraw the gas prof duced by this particular chamber and untilthe eduction 1nas been completed I then carry the material undertreatment, by gravity,

mechanically or otherwise into a succeeding chamber where it is againtreated at a higher temperature, for further eduction or volatilization,and I again draw off the gas produced in the second chamber as it iseduced. The same material is again subjected to volatilization in thethird, fourth or even more separate chambers and the withdrawal of theparticular gases therefrom. The kind, form and number of chambers used,the material from which constructed, degrees of heat of the respectivechambers, as well as the variation in the temperature between thecoolest and hottest chamber, depend on the grade and number of productsdesired. I have found that with our western shales not less than threestages are best and I prefer to begin operation with the first `chamberat a temperature of 100o F. and for the educt-ion and volatilization ofthe hea hydrocarbons such as paraffin and asphalttlie temperaturerequired for the hottest chamber may range from 900 to 14:00o F. ormore. v

Inasmuch as the gases generated at each successive step of the processare withdrawn before the bituminous material asses into the nextsucceeding;l chamber o? a higher temperature there is no possibility offluxing taking place, and it is found in actual operation that the shaleis at all times perfectly dry and dusty as soon as the water, usuallfound in such shales when first dug out o the earth, is driven o. I umthe term stage eduction to Iparticularl ditferentiate between my processand t at of zone vaporization as described in some patents heretoforegranted, and atterri Jted to be carried out in some plants, as I avefound that in the practice of zone vaporiza tion, it is impossible toprevent the mingling of the gases as produced in the adjacent successivezones of gradually increased temperatures. The zone demarkation is notpractical because the gases can not be kept absolutely separate andduring eduction or otherwise, when mingled or mixed more or lessunsaturated hydrocarbons will be developed or formed; and in refiningsuch4 eductions, more loss will occur from extra time and operationsrequired and a smalier per cent of oil recovered, on account of thehotter gasesof one zone circulating and coming in contact with the shaleof colder zones, thereby depositing by condensation or otherwise, theheavy fluids upon the shale particles which, when they reach the hotterzone and these fluids are again volatilized the fixed carbon or coke isleftgthereby cementing together the shale particles which is commonlyknown inV shale treatment as fluxing. This is entirely avoided in myprocess which I term stage eduction.

The decomposition of the lighter gases is caused by subjecting them to atemperature above that at which they are formed either i thru bringingthem into contact with the i thru separate pipes to their condensersthat by stage eduction I absolutely avoid the destruction ordecomposition of gases produced at lower temperatures such as is thecase when these lighter gases come in contact with the heavier gasesproduced at hight` r temperatures, as commonly practiced. I also findthat on account of no decomposition taking place, I am able to producean entirely fluid oil instead of the heavy greases which form atlmoderate temperatures by other processes. I also find that by condensingeach gas separately, and not permitting it to intermingle with the gasesproduce at higher or lower temperatures, that I avoid almost entirelythe complex yunrefinable combinations resulting from the unsaturatedhydrocarbons formed at different temperatures by other processes,thereby .making it possible to refine perfectly at a loss ofapproximately 6% compared with approximately 24% refining loss by otherprocesses. The condensation of the heavier uids on the particles of theshale and which cause the luxing in other processes also has the effectof converting the heavier iluids into lighter fluids. To accomplish thisin my process and also to be able to perfectly control the amount ofcondensation I carry this on outside of the retort in a condensingcylinder or chamber, the temperature of which I regulate in order toproduce a predetermined gravity oil or fluid. Such fluid as is condensedwithin this chamber is conveyed back through the pipe 30 into thecylinder of highest temperature where it is again volatilized. Byconveying the stream of condensed oil thus into the het shale over acomparatively small area I am able to eEect a perfect cracking ordecomposition of the heavier fluid and convert it into a lighter fluidwithout causing any iluxinvf whatever, owing to the fact that the fluidoes not become disseminated throughout the entire mass such as is thecase in other processes where condensation takes place directly on theshale. By this arrangement, I can automatically produce fluid or oil ofany desired gravity owing to the fact that it will continue to condenseand return t0 the cylinder automatically until it has reached su'chgravity as will enable it to pass this condenser. By this operation Ialso remove a large percentage of fixed carbon which attaches to thespent shale and passes out of the eduction chamber, thereby makingrefining of the fluid ,much sim ler and causing less fixed carbon to bedeposited in the coking stills.

Altho the distillation may be performed dry or without the use of steam,I prefer to use superheated steam in the process:

First, to enable me to volatilize at a lower temperature.

Second, to increase the oil yield by releasing hydrogen atoms from thesteam which combine with the carbon atoms in the material undertreatment.

Third, for the prevention of decomposition of the iron contained in theretort.

Fourth, to facilitate uniform heating Within the chamber.

I also find it advantageous especially when treating low grade shales toadd a small percentage of the non-condensable gases which I also passthru super-heating ipes in order that the gases may enter the c amber ata temperature as hi h as that at which eduction is being carrie onwithin that chamber.

I prefer to operate at or under a slight vacuum but some bituminousmaterial may be treated to advantage under pressure of one or moreatmospheres. The steps of my process may be carried out by moving thematerial under treatment from one chamber to another wherein the oilcontent is volatilized or it may be equally as well carried out bymoving the chamber, with its charge of material under treatment, fromone position in the furnace to another-where the chamber and contentsmay be subjected to the desired successive temperatures to volatilizethewoil content at the temperatures ranging from to 1400 or more degreesFahrenheit, and wherein the as ma be withdrawn as educted and wit iout alowing the gas produced at one position and temperature to mix with thegas educted at another tem erature. I have shown in the drawings iliedas a part of this application, a special form of furnace within whichthe steps of my process may beeconomically and efficiently carried outand in which Figure 1 is a side elevation, partly in section of saidfurnace.

Figure 2 is an end elevation of my furnace, parts cut away, and partsshown in section to show .the interior construction. Figure 3 is afragmentary View in elevation of a condenser system which I use inconnection with my furnace and in which portions of my process may becarried out.

n the drawings I show the inlet feed cylinder as l with the screwconveyor 2 as smaller in diameter than the cylinder l and mountedeccentricallv therein. A plurality of parallel horizontally disposedcylinders 3, are provided and secured one above the ing a gas ,other inparallel rows within a brick lined furnace A. A screw conveyor 5 isjournalled for rotation eccentrically in each of said cylinders 3 uponbearings 4, which bearings 4 are secured in the ends 24 of said furnaceA. The shafts of said screw conveyors 5 are suitably packed by thestufling boxes 13 in said bearings 4 to prevent the escape of gases fromthe said furnace. Each of said screw conveyors 5 is smaller in diameterthan its enclosing c linder 3 with the object of formliolding spacebetween the material carried along by the screw 5 and the wall of thecylinder. A bracket shelf, taking the form of a chute 6, is provided atone end of each of said cylinders 3 and at alternate ends thereof ineach vertical row to direct thematerial under treatment as it falls fromone cylinder into the end of the next succeeding cylinder. A pluralityof pipes 7 are secured transversely in said furnace to carry oi' the gasfrom said cylinders, and said pipes are connected with the condensers Bwhich are conveniently mounted and within which the gas -is condensed. Aslot or a number of perforations are provided on the lower side of thatportion of said pipe 7 which passes across or adjacent the open end ofeach cylinder 3 to receive the gas educed in that cylinder. A partialclosure in the form of a sleeve 10 is secured eccentrically in thealternate end portions of cylinders 3 and the said screw conveyors arecut off or removed at that point 1n order to form a closure of materialin the cylinder` which closure will be deposited and formed by thescrews piling up the material in said sleeve 10. A vertical metalpartition 12, which is `lined with fire brick, is provided and spacedfrom each of said ends, 24, of the furnace, and packing rings 11 areprovided therein to prevent the escape ofA gas and allow the expensionand contraction of the cylinders 3. A grate 14 is provided in the lowerpart and at one end of said furnace upon which fuel is burned to rovideheat for generating gas from the sha e as it is treated. A steamgenerating boiler 19 is provided and a pipe 15 conveys supersteamgenerated therein under the lower ones or row of said cylinders 3. Ascrew conveyor 18 is mounted in the lower portion of said furnace A tocarry away the gangue from the discharge hopper 17 Gear wheels 22 aresecured on the shafts of said screws 5 the teeth of which intermesh andthey are rotated by the belt 21 which is driven by the motor 20. Cleanout doors 26 are provided for removing the fuel ashes, while the fuel isfed thru the doors 25.

rlhe operation of my apparatus by which the steps of my process may becarried out is as follows:

rlhe shale to be treated is crushed and fed into the cylinder 1, and bymeans of the screw conveyor 2 is carried into all of the upper ones ofeach vertical row or tier of cylinders 3. As the crushed shale,frequently called herein, (the material under treat ment) is carriedthru said'cylinders 3 by their respective screw conveyors 5 it, (thematerial) is subjected to the heat of the burning fuel, as applied toand around the underside of the said cylinders 3, which fuel may besupplied on the grate 14 yand thru the gas burners 27, the gas beingsupplied thru the pipes 28 which may lead from the non-condensable gasesremaining after condensation in the condensers B. A space 9 is providedunder and partially around each of said cylinders 3 thru which the heatmay pass from the burnngfuel on said grate 14 and burners 27, upwardlyin a zigza path thru the successive spaces 9, as shown y the arrows aalternating from end to end of the furnace'and out thru the escape flue23. M the material under treatment is carried thru. each of saidcylinders 3 by its respective screw conveyor 5 the material is directedby ythe chute 6 into the next succeeding one below, where the screw ofthat cylinder catches it, and said material is carried in the oppositedirection, as shown by the arrows b, the screw of one cylinder beingrotated in opposite direction to that of the one above or below it bysaid intermeshin gear wheels 22.

As the material is passe thru said cylinders 3 the oil content of theshale is volatilized and passes or flows as a as out of that section ofsaid furnace A t ru the ipes 7 tothe respective condensers B, asindicated by the arrows c. The space within each cylinder 3 between thematerial carried therein and the overhanging wall of the cylinder,`which space is closed at one end by a bank of material deposited withinsaid sleeve 10, forms individual gas receptacles which open into theunder side of said pipes 7 thru the slot or perforations providedtherein. In this way I keep the gas remaining in this shale will bevolatilized as' said shale is drawn thru the cylinders in the secondtier and the gas generated there in will be drawn or flow off thru thesecond pipe 7 to another condenser and continuing on down in succeedinghorizontal tiers. the heavier oils will be subjected to the heat of thelowest tier of cylinders at a temperature of practically 1400o F. Thecondensate from any one or all of the condensers B may be returned forfurther volatilization thru the pipe 30 into the lowest and hottestcylinder 3. y

In treating some bituminous and volatile material it may be founddesirable to ll a receptacle with the material and then move thereceptacle or chamber from one portion of the furnace wherein a lowtemperature is maintained, to anotherfpart of the furnace, Where ahigher temperature 'is maintained, to educe thev volatile content of thematerial anddraw oii the gases generated at each temperature beforemoving to the position of a hi her temperature.

Having thus descried my process, and shown an apparatus within which thedifferent steps may be carried out,V I desire to secure by Letters'Patent and claim 1. The process for treating oil shale to produce oiltherefrom, which consists of subjecting the shale to various degrees ofheat while it is passing through coacting individual chambers;condensing the vapors of each chamber in another sepa-rate chamber; aain vola-tilizing the condensate of gsaid separate chambers by bringingit into contact with the shale under treatment in the chamber of highesttempera- 2. The process for treatin oil shale which consists ofsubjecting t e shale in separate chambers to varying degree of heat;leading oi the vapors from each chamber and separately condensing thesame to produce light oils; again volatilizing in a chamberrof highertemperature the heavy oils by contact with shale to carry off fixedcarbon on the shale gangue.

3. The process of treating oil shale which consists of subjecting thesha-le while in motion to heat in a plurality of chambers each of whichhas an increased temperature; separately condensing the vapors from eachchamber to produce oil; treating the condensate from all of saidchambers by contact with partially treated shale in a chamber of highertemperature to produce other oil vapors and to deposit carbon on theshale or removal therewith; and condensin@r the last mentioned oilvapors.

lln testimony whereof I have. aiixed my signature.

FJAMES B. JENsoN.

